CY7C027/028
CY7C037/038
Document #: 38-06042 Rev. *A
Page 2 of 19
Functional Description
The CY7C027/028 and CY7C037/038 are low-power CMOS
32K, 64K x 16/18 dual-port static RAMs. Various arbitration
schemes are included on the devices to handle situations
when multiple processors access the same piece of data. Two
ports are provided, permitting independent, asynchronous ac-
cess for reads and writes to any location in memory. The de-
vices can be utilized as standalone 16/18-bit dual-port static
RAMs or multiple devices can be combined in order to function
as a 32/36-bit or wider master/slave dual-port static RAM. An
M/S pin is provided for implementing 32/36-bit or wider mem-
ory applications without the need for separate master and
slave devices or additional discrete logic. Application areas
include interprocessor/multiprocessor designs, communica-
tions status buffering, and dual-port video/graphics memory.
Each port has independent control pins: dual chip enables
(CE0 and CE1), read or write enable (R/W), and output enable
(OE). Two flags are provided on each port (BUSY and INT). BUSY
signals that the port is trying to access the same location currently
being accessed by the other port. The interrupt flag (INT) permits
communication between ports or systems by means of a mail box.
The semaphores are used to pass a flag, or token, from one port to
the other to indicate that a shared resource is in use. The semaphore
logic is comprised of eight shared latches. Only one side can control
the latch (semaphore) at any time. Control of a semaphore indicates
that a shared resource is in use. An automatic power-down feature is
controlled independently on each port by the chip enable pins.
The CY7C027/028 and CY7C037/038 are available in 100-pin
Thin Quad Plastic Flatpack (TQFP) packages.
Pin Configurations
100-Pin TQFP (Top View)
Note:
6.
This pin is NC for CY7C027.
1
3
2
92 91 90
84
85
87 86
88
89
83 82 81
76
78 77
79
80
93
94
95
96
97
98
99
100
59
60
61
67
66
64
65
63
62
68
69
70
75
73
74
72
71
A9R
A10R
A11R
A12R
A13R
A14R
UBR
NC
LBR
CE1R
SEMR
OER
GND
NC
A15R
GND
R/WR
GND
I/O15R
I/O14R
I/O13R
I/O12R
I/O11R
I/O10R
CE0R
58
57
56
55
54
53
52
51
CY7C027 (32K x 16)
A9L
A10L
A11L
A12L
A13L
A14L
UBL
NC
LBL
CE1L
SEML
OEL
GND
NC
A15L
VCC
R/WL
GND
I/O15L
I/O14L
I/O13L
I/O12L
I/O11L
I/O10L
CE0L
17
16
15
9
10
12
11
13
14
8
7
6
4
5
18
19
20
21
22
23
24
25
34 35 36
42
41
39 40
38
37
43 44 45
50
48 49
47
46
33
32
31
30
29
28
27
26
CY7C028 (64K x 16)
[6]
[6]